Generally, membrane and pattern etching are repeatedly performed on a substrate such as a semiconductor wafer, and a plurality of desired devices are manufactured to manufacture a semiconductor integrated circuit.
To prevent interdiffusion between a material of a wire for connecting devices with each other and silicon diffused from a substrate such as a bottom layer or a Si-containing layer, barrier metal is typically disposed between a bottom layer and a wire. Such barrier metal has to be a metallic material having low electric resistance and high anticorrosion. A barrier metallic material capable of meeting such requirements mentioned above, such as an aluminum or tungsten wire that is currently used as a wire material, may be a high melting point metallic nitride, for example, Ti, W and Mo. A Ti or TiN film having electric and anticorrosive characteristics has been used as the barrier metallic material.
The Ti film or TiN film as the barrier metal is typically formed in a high temperature range of 500° C.˜700° C. according to chemical vapor deposition (CVD). The Ti or TiN may be effectively embedded in a contact hole or via-hole having a high aspect ratio and it has a good character with respect to aluminum or tungsten that is a wire material.
Recent demands on high integration and high microstructure of the integrated circuit have made the line width of wires get narrower. High operation efficiency as well as the high integration mentioned above is required. Under such situation, copper (Cu) with low resistivity and economic feasibility has been attracting attention as the wire material that can replace the aluminum. However, as mentioned above, the copper is vulnerable to migration with silicon like aluminum and to being diffused at a relatively low temperature. Accordingly, the copper (Cu) has an inadequate barrier capacity as the metal used in the Ti or TiN film.
Korean Patent No. 10-2009-0048523 discloses a method for using a TiSiN film deposited according to plasma CVD or thermal CVD to solve the disadvantage of the conventional Ti or TiN film. However, the concentration of chlorine and oxygen that are impurities contained in the TiSiN film deposited according to the chemical deposition method is high as shown in FIG. 1. Accordingly, a leakage current characteristic of a thin film manufactured might be deteriorated by the impurities.
As a result, there have been studied a method for forming a film having a reduced content of impurities contained in a manufactured TiSiN thin film.